The
track of mid-level rotation as seen by radar corresponding, in part, to
the Wisconsin record long-track tornado of May 16, 2017. (NWS-Chanhassen, Minnesota)

The
previous longest Wisconsin tornado path was also in northwest
Wisconsin, an 80-mile long path through Burnett, Pierce, Polk, and St.
Croix Counties on May 10, 1953, according to Tim Halbach, warning
coordination meteorologist at the National Weather Service office near
Milwaukee.
Modern historical tornado path records - dating to
1950 - are not as straight-forward as, say, temperature or precipitation
records.
(MORE: The Future of Tornado Warnings)
"Some
early long-track tornadoes, especially before the 1960s, are suspect
due to the lack of data for post-storm analysis," Jeff Last, warning
coordination meteorologist with the National Weather Service in Green
Bay, told weather.com in an email.
In this case, Halbach said in
an NWSchat entry Wednesday that a pair of seemingly longer-track
tornadoes from May 10, 1953 were likely not a single, continuous tornado
path, but rather a number of separate tornadoes from one parent
thunderstorm, known as a "tornado family."
Last said aerial
surveys, drones, high-resolution satellite imagery and dual-pol Doppler
radar all help present-day meteorologists determine if a supercell
produced multiple tornadoes or simply one long-track tornado.
In fact, a drone was used to assist in the Chetek tornado survey, according to NWS-Chanhassen.
(MORE: Most Tornado-Prone Counties in the U.S.)
The
most recent tornado with a comparably long path so far north happened
almost 30 years ago, a July 11, 1987 F3 tornado in Michigan's Upper
Peninsula, which was at least 71 miles long.
With historical
tornado paths of higher confidence, path lengths that long, while
thankfully uncommon, typically occur in the Deep South, central and
southern Plains, Ohio Valley or Lower Midwest.

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